1. Field of the Invention
The present invention relates generally to laser processing apparatus, and particularly concerns laser processing apparatus capable of work at plural work stations.
2. Description of the Prior Art
Laser apparatus for processing (for instance, cutting, drilling, welding, engraving, or heat processing of a workpiece) comprises a laser oscillator and an optical system for directing and focusing a laser beam on a work spot.
When constructing laser processing apparatus for actual manufacturing systems, it is possible to construct the apparatus to enable processing at plural work stations. To accomplish this laser processing apparatus is known which comprises one laser oscillator of a high power the, a beam-splitter for dividing output laser beam output of the laser oscillator into plural laser beams, plural wave-guides for directing the divided laser beam to the plural work stations, and focusing devices to focus the guided laser beam onto workpiece. One example of conventional laser processing apparatus having beam-splitter now will be described with reference to FIG. 1.
A laser oscillator 1 oscillates and issues a laser beam 6, which is divided into two laser beams 7 and 8 by a beam-splitter. The beam 7 irradiates a workpiece 4 at a first work station, and the other laser beam 8 irradiates, after reflection by a mirror 3, another workpiece 5 at another work station. However, a laser processing apparatus utilizing the conventional beam-splitter 2 has the following problem. Firstly, the output powers of the divided laser beams 7 and 8 are fixed to a certain levels, for instance, each about 50 W when the output laser beam 6 has a power of 100 W. That is, the ratio between the powers of two divided laser beams can not be changed as desired, and therefore when switching of the output power is desired, it is not easy to make such power adjustment. Furthermore, for the laser oscillator 1, a laser having consderably larger output, greater than the total of the powers used in plural work stations, has been neccessary. Furthermore, the beam-splitter 2 introduces light energy loss, and a half-mirror in the beam-splitter 2 receives considerable damage when the output power of the laser beam 6 from the laser oscillator 1 is high.